Eggs to Fry
This year we are inviting you to explore the lifecycle of a salmon through our virtual Eggs to Fry program. We will be raising a batch of salmon from eggs…to fry, when they will be released as baby salmon to continue their journey. We will post weekly updates on the salmon with photos and videos so you can follow along! When the fish are ready to be released you can help! We will have the fish, directions to where they can be released, and learning tools to talk with your kids (or friends) about their journey. We hope you follow along with us!
WEEK ONE- Egg Delivery!
Our eggs have arrived! The eggs delivered are at the eyed-stage. The black dots you can see in the first image on the left are their eyes developing and pretty soon we should see the eggs start to wiggle around as the body of the fish grows inside. Our tank has about 100 eggs in it, in the wild a female can lay 2,000-5,000 eggs. After maturing and living in the ocean for a few years, about 1% of the hatched fish will return to spawn! We hope to give them a great start to their journey and have 100 to release this fall!
Before the eggs were delivered we made sure our tank had cool clean water for the eggs to live in. We want the water as close to the river temp as possible which means making sure it stays between 48 and 53 degrees fahrenheit. The gravel on the bottom mimics the gravel that the female salmon build her redd out of. In the river the rocks would be much larger (think golf ball to baseball sized) and the nest/redd would be bigger than the tank!
We want to give a huge thanks to the Oregon Department of Fish and Wildlife for providing our education with these salmon eggs!
Week Two- advanced eyed eggs
Salmon lay their eggs in a nest called a redd. Buried deep within the redd, the soft-shelled eggs are protected from environmental risks and predators while they develop. At the early stages (fertilized to alevin) the fish are growing eyes, tails, and other body parts inside the egg! During this time, water quality is critical in our tank and in the wild! Dissolved oxygen is carried to the eggs from the water that flows over the gravel. If the water were to get murky, silty, or stop flowing, the embryos would die!
We continue to keep our tank cold and clean to support their development and give them the best chance at success!
Week three- alevin have emerged
Some of our eggs have hatched! After salmon hatch from their eggs, they are called alevin or sac fry. An enzyme is released that helps break down the wall of the egg so the alevin can emerge. If you look closely in the tank, you might see some pieces of the egg case floating around.
At this stage they are still very delicate and will remain in the redd for protection. Alevin rely on their yolk sac to provide the necessary nutrients to keep growing big and strong! Once they have fully absorbed their “sac lunch” they will emerge from the redd as fry!
Week four- wiggling sac fry
The alevin have developed into sac fry! Not much has changed in their general appearance. They are still holding onto the nutrient rich yolk sac and are becoming more active in the tank. They are developing more clearly defined fish parts and we will start to see colors and patterns that that are closer to what we expect fry to look like. As they grow, they will absorb more of the yolk sac before they are ready for release!